Engineering - We're Hiring - New
Senior Backend Engineer (Python/Node.js)
Remote - Full
At Callin.io, we're building the voice AI infrastructure that powers the next generation of human-machine conversations. Our platform handles millions of conversation minutes, enabling businesses to deploy intelligent voice agents that feel genuinely natural. We're a small, senior team moving fast on hard problems - and we're looking for engineers who thrive in that environment.
As a Senior Backend Engineer, you'll be at the core of everything we build. You'll design, scale, and maintain the distributed systems that make real-time voice AI possible at scale - from the async pipelines that process audio streams to the microservices that orchestrate complex conversational workflows. This isn't a role where you execute someone else's blueprint. You'll own entire systems, make meaningful architectural decisions, and see your work go live in production quickly.
You'll work closely with a tight-knit team of engineers who care deeply about reliability, performance, and code quality. Expect hard technical challenges, a high degree of autonomy, and the satisfaction of building something genuinely difficult.
Design and scale backend services handling high-throughput, low-latency voice data in real time
Build and maintain async workflows and event-driven pipelines that power live AI conversations
Architect resilient microservices that remain stable under load and gracefully handle failure
Integrate with telephony providers and real-time communication protocols (WebSockets, SIP, RTP)
Improve system observability, reliability, and performance across the stack
Collaborate on infrastructure decisions that shape how callin.io scales over the next few years
At Callin.io, we're building the voice AI infrastructure that powers the next generation of human-machine conversations. Our platform handles millions of conversation minutes, enabling businesses to deploy intelligent voice agents that feel genuinely natural. We're a small, senior team moving fast on hard problems - and we're looking for engineers who thrive in that environment.
As a Senior Backend Engineer, you'll be at the core of everything we build. You'll design, scale, and maintain the distributed systems that make real-time voice AI possible at scale — from the async pipelines that process audio streams to the microservices that orchestrate complex conversational workflows. This isn't a role where you execute someone else's blueprint. You'll own entire systems, make meaningful architectural decisions, and see your work go live in production quickly.
You'll work closely with a tight-knit team of engineers who care deeply about reliability, performance, and code quality. Expect hard technical challenges, a high degree of autonomy, and the satisfaction of building something genuinely difficult.
Real scale, real problems. You won't be pushing CRUD endpoints. You'll be solving latency challenges, designing for millions of concurrent audio streams, and building systems where reliability directly affects the user experience in real time.
Full ownership. We're a small team. There's no committee to approve your architecture or a backlog of tickets blocking your ideas. If you see a better way, you build it.
Async-first, fully remote. Work from wherever you do your best thinking. We care about outcomes, not office hours.
Voice AI is still wide open. The intersection of LLMs, real-time audio, and telephony is one of the most technically interesting spaces in software right now. You'll be working on it before most companies have even figured out what questions to ask.
Competitive compensation. Salary benchmarked to senior engineering roles at top-tier tech companies, regardless of your location.
Apply
Our hiring process is designed to be respectful of your time while giving us confidence you're the right fit.
01
Application Review: 15-30 minutes Submit your application with resume/portfolio. We review every application personally and respond within 5 business days.
02
Initial Screen: 30 minutes Quick video call with our recruiting team to discuss your background, the role, and answer initial questions.
03
Technical/Skills Assessment: Varies by role For engineering roles: coding challenge or take-home project. For other roles: case study, portfolio review, or role-specific exercise.
04
Team Interviews: 2-3 hours total Meet potential teammates and leadership. We typically schedule 2-3 conversations covering technical skills, culture fit, and role-specific deep dives.
05
Final Decision: 2-3 days We move quickly. You'll hear our decision within 2-3 days after final interviews. If it's a yes, we'll extend an offer immediately.
Total Timeline: 2-3 weeks from application to offer